+HOT Competition 4 Sep/9AM: Paleontologists have discovered the fossil

Hi dharam9610

My friend,

I am far from being an expert (I wish I was, though). I would advise you not to expend much time on unofficial verbal problems because you may wind up learning wrong things – the worst damage you can inflict on yourself. It’s equally advisable not to read my explanations written under a time constraint; I may have missed some clues or may simply be wrong.

This problem, as written, is faulty. It’s based upon an official problem you can find here. Below is a spoiler:

- Astronomers have discovered a distant supernova explosion, one they believe to be of a type previously unknown to science. (correct)

The entire phrase “one they believe… to science” is an appositive that gives additional information about the closest noun phrase “a distant supernova explosion”. Because “one” refers to “a distant supernova explosion”, you can replace one with the other to get the meaning:

- Astronomers have discovered a distant supernova explosion, a distant supernova explosion they believe to be of a type…

To keep the sentence concise, though, we simply use “one”. If the modified noun is not that long, we can just repeat it as in here. Below is a spoiler:

- Yellow jackets number among the 900 or so species of the world's social wasps, wasps that live…

In any case, an appositive is a modifier that cannot stand on its own. Now take the correct choice of this problem:

- Paleontologists have discovered the fossilized remains of a 66 million year old Gondwanatherian mammal; one they believe to be of a species previously unknown to science.

Here, the entire “one they believe… to science” tries but FAILS to serve as an appositive. In the original problem, the appositive is correctly appended to the sentence by a comma. However, here, the ostensible appositive is separated by a semicolon – a big mistake because a semicolon MUST start another sentence, not a modifier. So, all choices are wrong because none is a sentence, but fragments. Such a small thing as “;” can ruin the entire problem.

If there were a comma though, your analysis would mostly be correct:

- Paleontologists have discovered the fossilized remains of a 66 million year old Gondwanatherian mammal, one they believe to be of a species previously unknown to science.

Here, “one” refers to “a 66 million year old Gondwanatherian mammal”. The remaining part “they believe… to science” is a noun modifier describing “one”. Everything seems fine.

Let’s sort out choice A now:

- Paleontologists have discovered the fossilized remains of a 66 million year old Gondwanatherian mammal, one that they believe is a species previously unknown to science.

Here, “they believe” is simply an adverbial modifier. Such modifiers usually give some emphasis, but are not important to the central meaning of the sentnece, and thus can merely be omitted. For example:

- This car I think is the fastest among the electric sedans.
- This car is the fastest among electric sedans.

A similar official problem is here . Below is a spoiler:

- The electronics company has unveiled what it claims is the world’s smallest network digital camcorder
- The electronics company has unveiled what is the world’s smallest network digital camcorder

Similar HOT problem:

- During the performance, a challenging work by an artist who devotees say has become ever more open to meta-reflection and revision, Abramović reconnected…
- During the performance, a challenging work by an artist who has become ever more open to meta-reflection and revision, Abramović reconnected…

So, we can read A without “they believe” as “one that is a species…” or “a mammal that is a species…”. We can see how A illogically implies that “one = a mammal” itself is an unknown species. Nonsense. One mammal itself cannot constitute a species; rather, it can be of unknown species, or of a species previously unknown to science.

Also note that we CANNOT eliminate A, saying that “one that” is redundant, as many did in this thread. Check this official problem. Below is a spoiler:

- Being heavily committed to a course of action, especially one that has worked well in the past, is likely to make…

Another thing worth noting: “one” actually can refer to “fossilized remains”, but will imply only one “remain”. An example from MGMAT SC guide:

- After walking by the chocolates so many times, Roger finally had to eat one (one chocolate).

In case you wonder why other choices are wrong, check GMATGuruNY ‘s post here .

About "one" read RonPurewal here .